How to detect someone tapping outside of a UIImageView - ios

Question

I have a UIImageView that is added as a subview. It shows up when a button is pressed.
When someone taps outside of the UIImageView in any part of the application, I want the UIImageView to go away.
#interface SomeMasterViewController : UITableViewController <clip>
<clip>
#property (strong, nonatomic) UIImageView *someImageView;
There are some hints in stackoverflow and Apple's documentation that sound like what I need.
Apple's : Gesture Recognizers
Apple's : UIView hitTest:withEvent
Apple's : UITouch Class Reference
Stackoverflow: Listening to UITouch event along with UIGestureRecognizer
(not likely needed but..) - CGRectContainsPoint as mentioned in the following post titled: Comparing a UITouch location to UIImageView rectangle
However, I want to check my approach here. It's my understanding that the code needs to
Register a UITapGestureRecognizer to get all touch events that can happen in an application
UITapGestureRecognizer should have its cancelsTouchesInView and
delaysTouchesBegan and delaysTouchesEnded set to NO.
Compare those touch events with the someImageView (how? Using UIView hitTest:withEvent?)
Update: I am registering a UITapGestureRecognizer with the main UIWindow.
Final Unsolved Part
I have a handleTap:(UITapGestureRecognizer *) that the UITapGestureRecognizer will call. How can I take the UITapGestureRecognizer that is given and see if the tap falls outside of the UIImageView? Recognizer's locationInView looks promising, but I do not get the results I expect. I expect to see a certain UIImageView when I click on it and not see the UIImageView when I click in another spot. I get the feeling that the locationInView method is being used wrong.
Here is my call to the locationInView method:
- (void)handleTap:(UITapGestureRecognizer *)gestureRecognizer
{
if (gestureRecognizer.state != UIGestureRecognizerStateEnded) {
NSLog(#"handleTap NOT given UIGestureRecognizerStateEnded so nothing more to do");
return;
}
UIWindow *mainWindow = [[[UIApplication sharedApplication] delegate] window];
CGPoint point = [gestureRecognizer locationInView:mainWindow];
NSLog(#"point x,y computed as the location in a given view is %f %f", point.x, point.y);
UIView *touchedView = [mainWindow hitTest:point withEvent:nil];
NSLog(#"touchedView = %#", touchedView);
}
I get the following output:
<clip>point x,y computed as the location in a given view is 0.000000 0.000000
<clip>touchedView = <UIWindow: 0x8c4e530; frame = (0 0; 768 1024); opaque = NO; autoresize = RM+BM; layer = <UIWindowLayer: 0x8c4c940>>

Answer 1

I think you can just say [event touchesForView:<image view>]. If that returns an empty array, dismiss the image view. Do this in the table view controller's touchesBegan:withEvent:, and be sure to call [super touchesBegan:touches withEvent:event] or your table view will completely stop working. You probably don't even need to implement touchesEnded:/Cancelled:..., or touchesMoved:....
UITapGestureRecognizer definitely seems like overkill in this case.

Answer 2

You can use touch functions to do that:
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event;
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event;
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event;
- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event;
when user touch the screen first your touchBegan function is called.
in touchBegan:
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
CGPoint pt = [[touches anyObject] locationInView:self];
}
so you have the point that user touched.Then you must find that the point is in your UIImageView or not.
But if you can give tag to your UIImageViews. That will be pretty much easy.
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{
UITouch *touch = [touches anyObject ];
if( yourImageView.tag==[touch view].tag){
[[self.view viewWithTag:yourImageView.tag] removeFromSuperView];
[yourImageView release];
}
}